You need to take advantage of your metabolism to lose/maintain weight. Maximize it by eating something every 3 hours or so. When you finish eating something, see what time it is and add 3 hours which is when you will eat again.
Since you would be eating several times a day, don't eat too much. If you are concerned about consuming too many calories, eat foods that are low in them. In other words, foods that are made mostly of water such as fruits and vegetables. Fresh fruit, not dry (raisins and prunes are dry and have way more calories per ounce than fresh grapes for example).
If you eat this way then your body will constantly burn calories and you don't even have to exercise. Of course I recommend exercise as well to speed up the process.
Finally, if you insist on eating just a little bit of food a day, I think you should take a multivitamin daily to ensure that you are getting proper nutrition.